1) Washing soda is hydrated sodium carbonate, Na2CO3. xH20. A student wished to determine the value of x by carrying out a titration, with the following results:

5.13 g of washing soda crystals were dissolved in water and the solution was made up to 250 cubic cm in a standard volumetric flask

25.0 cubic cm of this solution reacted exactly with 35.8 cubic cm of 0.100 mol. dm-3 hydrochloric acid and carbon dioxide was produced.

(a) (i) Write a balanced equation for the reaction between Na2CO3 and HCI.

(ii) Calculate the amount, in moles, of HCl in the 35.8 cm3 solution used in the titration.

(iii) Use your answers to (i) and (ii) to calculate the amount, in moles, of Na2CO3, in the 25.0 cubic cm of solution used in the titration.

(iv) Use your answer to (iii) to calculate the amount, in moles, of Na2CO3, in the 250 cm3 of solution in the standard volumetric flask.

(v) Hence, calculate the mass of Na2CO3, present in 5.13 g of washing soda crystals.